This document specifies a methodology and provides related requirements, recommendations and guidance for the design and integration of safety‐related parts of control systems (SRP/CS) that perform safety functions, including the design of software.


This document applies to SRP/CS for high demand and continuous modes of operation including their subsystems, regardless of the type of technology and energy (e.g. electrical, hydraulic, pneumatic, and mechanical). This document does not apply to low demand mode of operation.


NOTE 1        See 3.1.44 and the IEC 61508 series for low demand mode of operation.


This document does not specify the safety functions or required performance levels (PLr) that are to be used in particular applications.


NOTE 2        This document specifies a methodology for SRP/CS design without considering if certain machinery (e.g. mobile machinery) has specific requirements. These specific requirements can be considered in a Type‑C standard.


This document does not give specific requirements for the design of products/components that are parts of SRP/CS. Specific requirements for the design of some components of SRP/CS are covered by applicable ISO and IEC standards.


This document does not provide specific measures for security aspects (e.g. physical, IT-security, cyber security).


NOTE 3        Security issues can have an effect on safety functions. See ISO/TR 22100-4 and IEC/TR 63074 for further information.